Update 2.39pr: Overhaul of custom level screen, QOL enhancements

Update 2.39pr

• Custom level select screen now shows which custom levels are empty

• Custom level select screen now has a toggle for edit/play

• If 'edit' is selected, choosing a level opens the level in the editor

• If 'play' is selected, choosing a level opens the level to play, exiting the level goes back to custom level select

• Player speed preference now saves between gameplay sessions

• Move counter and end-level results on by default (turn off with "V" or in options)

• Achievement for achieving par on all bonus levels is now functional

• Minor bugfixes